Imported from previous forum
[ original email was from Jim Northey - jnorthey@jandj.com ]
This is one of those splitting hairs semantics questions - should we label FAST as a presntation level protocol - much as CORBA, XDR, CDR, etc. are considered presentation level protocols. It doesn’t seem appropriate to call FAST an application level protocol - because without some application and specific usage - there is not much value to FAST - similar to any other marshalling / demarshalling mechanism.
[ original email was from Donald Mendelson - dmendelson@cmcplace.com ]
> This is one of those splitting hairs semantics questions - should we
label FAST as a presntation level protocol - much as CORBA, XDR, CDR,
etc. are considered presentation level protocols. It doesn’t seem
appropriate to call FAST an application level protocol - because without
some application and specific usage - there is not much value to FAST -
similar to any other marshalling / demarshalling mechanism.
In terms of the OSI model, FAST and FIX are mainly in the Presentation Layer, which is concerned with data representations of messages.
In the model, each layer only interacts with its adjacent layer. Presentation interacts with Application above and Session Layer below.
[ original email was from Natan Kugel - Natan.Kugel@charter.net ]
> > This is one of those splitting hairs semantics questions - should we
label FAST as a presntation level protocol - much as CORBA, XDR, CDR,
etc. are considered presentation level protocols. It doesn’t seem
appropriate to call FAST an application level protocol - because
without some application and specific usage - there is not much value
to FAST - similar to any other marshalling / demarshalling mechanism.In terms of the OSI model, FAST and FIX are mainly in the Presentation
Layer, which is concerned with data representations of messages.In the model, each layer only interacts with its adjacent layer.
Presentation interacts with Application above and Session Layer below.
To my knowledge, FIX / FAST are addressing both session and presentation levels of OSI. However, implementation sometimes deals with application level, if it addresses issues related to different interpretations of fields. Jim opened a good question worth following – should we further segregate session level and presentation levels in order to address multitude of transports (UDP and TCP/IP). This will also help gaining independence for presentation layers as well as sharing them in both FIX / FAST.